The standard library rlcompleter doesn't support expressions involving
an item lookup (e.g., x[0] or x['foo']). This is a pain for the drgn
CLI, because it's common to use prog['variable'] and want to
autocomplete it. Instead of using the standard library rlcompleter,
implement our own, cleaned up version of it with the ability to handle
expressions containing [key]. rlcompleter already allows for arbitrary
__getattr__() calls, and __getitem__() isn't any different.
This is a big change that makes EnumType have a compatible integer type
member instead of copying the fields, which ends up touching a lot of
stuff but also fixing a bunch of static typing errors.
Converting an lvalue to an operand has to do a little bit more than
remove qualifiers:
- Convert array types to pointer types
- Convert function types to pointer types
Some types don't actually have to go through find_dwarf_type(), so they
can be handled in the common code. This allows us to add a MockTypeIndex
to the tests.
The rules are really subtle and not completely specified, so hopefully
this covers all of the corner cases... This will be used for
ProgramObject operators.
Instead, take callbacks for looking up variables and reading memory.
While we're at it, get rid of TypeFactory and instead implement its
methods as functions taking a DwarfIndex.
Most of drgn.dwarf is not performance-sensitive, and the part that is
(DwarfIndex) can use some extra tuning which is easier to do in C rather
than Cython.
The lldwarf/drgn.dwarf split wasn't working out too well, and moving all
of drgn.dwarf into lldwarf (by rewriting it into C) would be way too
much work. Instead, use Cython, which results in a parser which is just
as fast but with much cleaner code overall. It also turns out lldwarf
wasn't doing GC right, so the switch also fixed that.
Resolving parameters, variables with function scope, and global
variables should work. This is just the variable resolution, no fetching
yet, but a bunch of refactors snuck in here so committing it all now.
The parsing library shouldn't really care about keeping track of these.
Instead, add __dict__ and getattr()/setattr() to all of the lldwarf
objects so higher layers can store the offset if they want.
DwarfDie is special in two ways:
1. We want to store an offset for the DIE so we know where to parse
sibling and children entries.
2. For some attributes, we need to store an offset so we know where to
find them later.
Both of these are changed to be relative to the CU rather than the
buffer.
I wrote all of this code a few months back and am just now getting
around to committing it. The low-level DWARF parsing library is pretty
solid, although it only implements a subset of DWARF so far. The CLI and
higher-level interface are experimental.
